bpo-32356: idempotent pause_/resume_reading; new is_reading method. (#4914)

1 files changed, 7 insertions, 8 deletions

diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index cb33cd3..3f44a99 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -702,22 +702,21 @@ class _SelectorSocketTransport(_SelectorTransport):
             self._loop.call_soon(futures._set_result_unless_cancelled,
                                  waiter, None)
 
+    def is_reading(self):
+        return not self._paused and not self._closing
+
     def pause_reading(self):
-        if self._closing:
-            raise RuntimeError('Cannot pause_reading() when closing')
-        if self._paused:
-            raise RuntimeError('Already paused')
+        if self._closing or self._paused:
+            return
         self._paused = True
         self._loop._remove_reader(self._sock_fd)
         if self._loop.get_debug():
             logger.debug("%r pauses reading", self)
 
     def resume_reading(self):
-        if not self._paused:
-            raise RuntimeError('Not paused')
-        self._paused = False
-        if self._closing:
+        if self._closing or not self._paused:
             return
+        self._paused = False
         self._loop._add_reader(self._sock_fd, self._read_ready)
         if self._loop.get_debug():
             logger.debug("%r resumes reading", self)